Magnet-rail for electrical musical instruments.



M. L. SEVERY & G. B. SINCLAIR.

MAGNET RAIL FOR ELECTRICAL MUSICAL INSTRUMENTS. APPLICATION FILED JAN-4,1913.

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M. L. SEVERY & G. B. SINCLAIR.

MAGNET RAIL FOR ELECTRICAL MUSICAL INSTRUMENTS.

APPLICATION FIiED IAN-4| I913.

Patented Dec. 19, 1916.

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MELVIN L. SEVERY,

OF ARLINGTON HEIGHTS, MASSACHUSETTS, AND GEORGE B.

SINCLAIR, OF GEORGETOWN, MAINE, ASSIGNOBS T0 CHORALCELO COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

MAGNET-BAIL Fort ELECTRICAL MUSICAL INSTRUMENTS.

Specification of Letters Patent.

Patented Dec. 19, 1916.

Application filed January 4, 1913. Serial No. 740,201.

To all whom it may concern:

Be it known that we, MELVIN L. SEVERY, of Arlington Heights, in the county of Middlesex and Commonwealth of Massachusetts, and GEORGE B. SINCLAIR, of Georgetown, in the county of Sagadahoc and State of Maine, both citizens of the United States, have invented certain new and useful mprovements in Magnet-Rails for Electrical Musical Instruments, of which the following is a full and exact description.

This invention relates to musical instruments comprising tuned electromagnetically attractive sonorous bodies vibrated by means of closely disposed electromagnets having1 properly timed electric pulsations delivere thereto; and this invention has for its objects the construction of improved means for supporting said electromagnets; and to improvements in the electromagnets themselves.

Referring to the drawings forming part of this specification, Figure 1 is an elevation of a rail for the support of the electromagnets embodying one form 'of the i nvention. Fig. 2 is a cross section of the same on the line XX in Fig. 1. Fig. 3 is a cross section on the line Z-Z in Fig. 1. Fig. 4 is a top view of the magnet rail and of magnets carried thereby. Fig. 5 is a sectional detail view of one of the spherical nuts used in the rail. Fig.-6 is a perspective view of a musical instrument showing the position of the magnet rail and connect- 11 is a front elevation of a part of the same.

Fig. 12 is a side view of one of the base electromagnets. Fig. 13 is a side view of one of the treble electromagnets.

The sonorous bodies illustrated in the drawings are strings 1 of the usual piano type, vibrated by means of electromagnets 2 supported by a magnet rail 3 and receiving current from a source 4, through makeand-break devices comprising brushes 5 and toothed disks or rings 6, and connections consisting of a common lead wire 8 betweensaid source and all the magnets, a wire 9 from each magnet to a brush 5, and a brush 10 and wire 11 between said source and members 6. The circuit through each wire 9being controlled by a pair of contacts 7, 7*, by means of keys, or in any other manner. In Letters Patent No. 1,097,052 granted to us under date May 19, 1914,we have shown and described a magnet rail comprising two sections pivotally connected at their proximate ends, and pivotally supported at their remote ends upon brackets rindered capable of adjustment forward and backward, and having means for securing the brackets in their adjusted positions. The proximate ends of the rail sections were, under the patented construction, connected with a pedal or lever whereby said sections and their magnets might be moved toward and from the strings or other tuned sonorous bodies with which they were asso ciated. By the patented construction provision was made for adjusting the entire magnet rail bodily forward and backward and for adjusting said rail bodily by a movement about the pivotal support of either end, the end supports in each case being rigidly fixed in their adjusted positions. Finally, the meeting ends of the rail sections were drawn toward the strings or other sonorous bodies by a spring, and were movable from the strings through the pedal and intermediate connections.

Under the present construction provision is made not only for moving the magnetrail bodily toward and from the strings or other sonorous bodies, or moving either en forward or backward and clamping the ends in their adjusted positions, but also for ti ping the rail transversely so as to bring t e oles of the magnets into planes parallel with the strings or sonorous bodies; for ad- .justing the individual magnets axially and them in any desired direction relathe meeting ends of the rail sections towar the rotative adjustment of the rail.

and from the strings or sonorous bodies and looking or securing them in adjusted position. By our improved construction we secure not only the several adjustments afforded by the patented construction, but we also provide for more perfect adjustment of the magnets individually and collectively.

As in the patented structure, so here, the upper'treble magnets are placed nearest their associated strings, the low bass magnets slightly farther from their strings, and the intermediate magnets at a greater distance from their strings than either the upper treble or low bass magnets.

As shown in Fig. 1, the two sections 12 and 13 of the rail are hinged together by means of a metal strap 14 fixed to the end of section 12 and having ears 16 formed with slots or notches 15 (Fig. 4) through which are inserted pins 17 into the section 13. Immediately above said hinge is a finger 18 adapted to engage the annular groove 21 of a screw 20 (Figs. 1 and 3) in a manner to support such hinged portion of the rail, said screw turning in suitable parts of the frame 23. By turning said screw, the intermediate portion of the rail is moved toward or from the strings, the parts more removed from the hinge being shifted to lesser extents.

The extreme bass end of the section 12 is adjustably supported by means of a bar 24 fastened thereto (Figs. 1 and 2) through the midlength of which bar passes a screw 25 tapped into a spherical nut 26 confined in a block 27 (Figs; 2 and 5), the head of said screw being formed with a groove 29 engaged by a finger 30 fixed to the string plate 28. The rotation of said screw. serves to pull or push the railthereat in accordance with the direction of such rotation. Tapped through said plate 28 above and below said rail are screws 31 abutting against the ends of said bar 24, and adapted by their opposite turning to angularly adjust the rail on its longitudinal axis as a center. The three screws acting together permit of the bodily adjustment toward or from the strings.

For the treble end of the rail section 13, a single screw 32 may be employed, coacting with a spherical nut 33 (Figs. 1', 4) and in all other ways controlled like the screw 25 above described. This spherical nut allows In this way the magnet rail is enabled to be adjusted in all ways necessary for the presentation ofthe magnets 2 to their strings at accurately determined distances therefrom.

The magnet rail wood, but we prefer to use metal as far less liable to be afiected by hygrometric conditions, and warping, swelling and splitting. en of metal, the rail sections may be comparatively thin, as shown in Figs. 8 and 9, and are stifl'ened by flanges 34. (in the thus far described is of.

face of each section are several rows of lugs 35 between which slidably fit the yokes 36 of the electromagnets 2, in order to insure against their shifting either laterally or angularly. For the individual adjustment of each magnet, four screws are provided, the central one 37 of which is tapped into said part 36 but turns freely in the rail, while'the other screws 39 are tapped through the rail and set against the surface of said part. These four screws allow ofa slight but sufiicient angular adjustment in any direction, and also of a bodily movement of the magnet toward and from its string, but at the same time confining the magnet firmly in position. These adjustments are of exceedingly great value, for the reason that if one pole of a magnet is nearer its string than the other, the nearer pole may be struck by the string and cause a hi hl objectionable metallic twanging. Or, i the nearer pole is sutficiently removed to be out of danger of such striking, the other pole will be so far away as to be practically without effect upon the string.

For perfect work, both poles of every magnet must be equally removed from its string, and yet as close thereto as possible,

in order to give a maximum attractive ef-' feet, while being just beyond possible contact therewith. This will be realized more fully when it is recalled that the attraction for its armature varies in inof a magnet the squares of its disindependent of each other. ere a suitably supported bracket 40 is provided with two sets of three screws, one set for one rail section, and the other set for theother secsurface, and the outermost screws 42 are tapped through the same, the effect being precisely like that of the screws 25 and 31 above described, since as we have found, the adjustment required is so slight as not to require the spherical nut 26. On the other hand, the cost is considerably less for the last-described construction.

A similar bracket 44 (Fig. 8), with like screws 41, 42, is provided for each of the other ends of the rail-sections, (Figs. 7 and 8) so that each section can be adjusted both angularly and bodily to present the magnets as a whole at the proper distances from the strings; while the above-described individual adjustment of the electromagnets cares for the finer inaccuracies of position.

The main object of the lugs 35 is to keep the electromagnets from turning on the screws 3? a plane parallel with 'the'face (tn? the rail, and to hold them plumb and rue.

We have discovered that it is desirable to vary the lengths of the yokes 36 of the electromagnets, the bass magnets having said members 36 quite long, as in Fig. 12, the treble magnets having them quite short, as shown in Fig. 13, and the intermediate parts 36 being of medium length, as in Fig. 9. The purposes of such variations are two-fold: first, to avoid the leakage across the poles of each magnet when the poles are near together. It is necessary to have the poles of the upper electromagnets close together in order that both poles may be close as possible to the proper striking points of the strings, since the shortness of the upper treble strings correspondingly limits the space allowable for the striking points. As the lengths of the strings increase, the distances between the magnetpoles can be increased, and the magneticleakage reduced to a minimum. The second purpose accomplished by the increase in length of the yokes 36 is to materially augment the amount of iron in the magnets an thus to increase the strength of the magnets and with it the loudness of the notes produced, without change in current-strength. This lengthening of the yokes is more eiiicient and economical to do than to increase the diameters of the cores 2, although this also is done, as shown in Figs. 9, 12 and 13.

The dimensions of the magnets may vary considerably. without destroying the efliciency of the instrument, but our experience has caused us to adopt in practice of an inch as the preferred diameter of cores for magnets of the extreme treble strings, with a spacing of of an inch between core axes; and a diameter of of an inch for the cores of the magnets of the lowest bass strings, with a spacing of 1%,; inches between the axes of said cores. Themagnet yokes are, in practice, made of Norway iron A; of an inch in thickness, A of an inch in width, and of a length proportionate to the separation of the cores, it being material only that there be suflicient iron in the yokes, or in other words, a surplus causing no ill effects.

The magnet windings we find convenient and suitable are of Nos. 25 and 26 enameled or cotton-covered copper wire, wound to offer 20 ohms resistance in the case of the extreme lower bass string magnets, an ohms resistance in the case of the extreme treble string magnets.

Theoretically,

cores, and resistance offered by the windings, should vary between the selected limits or extremes, progressively and uniformly from magnet to magnet This, cable,

throughout the series. however, is commercially impractiand the following have been adopted dimensions and spacing of theoretical and commercial considerations:

- Core Separation Notes diameters. of core axes.

/ j l w 1-25 20 ohms iinch 11;" inches. 12 ohms i inch linch. 9ohms iinch linch. 5 ohms & inch 1 inch.

5ohms kinch flinch.

What we claim as our invention and for which we desire Letters Patent is as follows, to wit 1. A musical instrument comprising magnetically attractive sonorous bodies and electric means including electromagnets for the vibration of said sonorous bodies; a magnetrail for the support of said electromagnets; means for adjusting said rail bodily toward and from said sonorous bodies and for angularly adjusting the rail about its longitudinal axis; and means for rigidly securing said rail in adjusted position.

2. A musical instrument comprising magnetically attractive sonorous bodies and electric means including electromagnets for the vibration of a magnet said sonorous bodies; rail for the support of said electromagnets, said magnet-rail being in a plurality of sections adjustable at their proximate ends relative to said sonorous bodies; and means for rigidly securing said proximate ends in adjusted position.

3. A musical instrument comprising magnetically attractive sonorous bodies and elec tric means including electromagnets for the vibration of said sonorous bodies; a magnet-rail for the support of said electromagnets, said rail being in two sections adjustable at their proximate ends relative to sai sonorous bodies; and means for rigidly securing said proximate ends in adjusted position.

4. A musical instrument comprising magnetically attractive sonorous bodies and elec tric means including electromagnets for the vibration of said sonorous bodies; a magnetrail for the support of said electromagnets, said rail being in two sections; means for bodily adjusting the rail sections toward and from said sonorous bodies; means for angularly adjusting said rail sections about their longitudinal axes; and means for rigidly securing said sections in their adjusted positions.

5. A musical instrument comprising magnetically attractive sonorous bodies and electric means including electromagnets for the vibration of said bodies; a magnet-rail for the support of said electromagnets; fixed brackets at the ends of said rail for supporting the same; and means connected with said brackets for adjusting said rail bodily toward andfrom the brackets and angularly with reference thereto, and serving also to secure the rail in its adjusted position.

6. A musical instrument comprising magnetically attractive sonorous bodies and electric means including electromagnets for the vibration of said bodies, a magnet rail for the support of said electromagnets, suitably supported brackets, and three screws the support of said electromagnets, suitable supporting means, and three end of said rail held by said supporting means, said three screws being in a sub stantially vertical line, the intermediate screw pushing against the rail and the outermost screws being tapped into and pulling the rail.

8. A musical instrument comprising magnetically attractive sonorous bodies and electric means including electromagnets for the vibration of said bodies, a magnet rail for the support of said electromagnets, said magnet rail being in sections, brackets suit a ly supported at the ends of said sections, and three screws engaging each end of said sections and held by said brackets.

musical instrument comprising magnetically attractive sonorous bodies and elecnetically attractive sonaous bodies and electrio means including electromagnets for the vibration of said serving to angularly adjust and hold the magnet-yoke in adjusted position.

11. A musical instrument comprising a magnet-rail; a series of electromagnets carried by said rail; tuned sonorous bodies located in attractive relation to and serving as armatures for said electromagnets means for adjusting the electromagnets toward and from the tuned for said lateral play or movement thereof during adjustment toward and from'the rail.

12. A magnet rail for electric musical instruments having rows of lugs upon its outer face, in combination with electromagnets fitting between said lugs, and screws for adjusting the position of each electromagnet toward and from the magnet rail.

13. A magnet rail for electric musical instruments having a plurality of longitudinally disposed rows of lugs upon its outer face, in combination with electromagnets havingyokes slidable between said lugs, and screws adapted both to push and pull said electromagnets relative to the rail.

14. A magnet rail for electric musical instruments having a plurality of longitudinally disposed rows of lugs upon its outer face, in' combination with electromagnets having yokes slidable between said lugs, a pluralitv of screws turning in the rail for each yoke adapted to push the latter away from the rail, and a centrally disposed screw for each yoke adapted to draw the latter toward the rail.

15. A musical instrument comprising magnetically attractive sonorous bodies, electric means including electromagnets for vibrating said bodies, and a magnet rail for supporting said electromagnets, said rail being each adapted both for angular and bodily adjustment relative to the said bodies, and each of said electromagnets having means for its individual angular and bodily adjustment relative to said bodies.

16. A musical instrument comprising magnetically attractive sonorous bodies of pitches, and electric means including electromagnets for the vibration of said bodies, said electromagnets being provided with difi'erent amounts of iron, the amounts being greater for the magnets associated with sonorous bodies of lower pitches than for the magnets associated with the sonorous bodies of higher pitches, substantially as set forth.

musical instrument comprising magbodies of widely difl'erent pitches,- and electric means including electromagnets for the vibration of shaid bodies, the electromagnets associated wit and means for delivering electric pulsations to said electromagnets, oi a magnet rail for supporting said electromagnets, a fixed with a plurality of jointed at an intermediate point and provided with hinging means thereat consisting of a terminally slotted fork and pins 15 entering the slots, and supporting and adjusting means consisting of a screw projecting from and turning in said plate, and an arm rising from the rail at such joint in engagement with the screw. 20 In testimony that we claim the foregoing invention, we have hereunto set our hands this 10th day of December, 1912.

MELVIN L. SEVERY. GEORGE B. SINCLAIR.

Witnesses EDWARD S. OROCKETT,

A. B. UPHAM. 

